1. Field of the Invention
The present invention relates to a propulsion device arranged to propel a hull.
2. Description of the Related Art
A propulsion device according to a prior art is an outboard motor described in Japanese Published Unexamined Patent Application No. 2006-219130. The outboard motor includes an outboard motor main body, an attachment mechanism arranged to attach the outboard motor main body to a hull, a steering mechanism arranged to turn the outboard motor main body right and left, and a tilt mechanism arranged to turn the outboard motor main body up and down.
The attachment mechanism includes a swivel bracket coupled to the outboard motor main body so as to turn about a swivel shaft that extends vertically, and a clamp bracket coupled to the swivel bracket so as to turn about a tilt shaft extending horizontally in a right/left direction. The clamp bracket is fixed to a stern plate provided at a rear portion of the hull. The tilt shaft is arranged above the stern plate.
Also, the steering mechanism is arranged in front of the tilt shaft. The steering mechanism is exposed. The steering mechanism includes a ball screw arranged horizontally along the right/left direction, and a motor coupled coaxially to the ball screw. The ball screw is arranged in front of the tilt shaft and at substantially the same height as the tilt shaft. Both end portions of the ball screw are fixed to the swivel bracket. Also, the motor is coupled to the outboard motor main body via a coupling member.
When the motor is driven to rotate, the motor moves in an axial direction along the ball screw. The coupling member is turned to the right or the left about the swivel shaft in accordance with the movement of the motor. The coupling member and the outboard motor main body are thereby turned to the right or the left about the swivel shaft with respect to the hull. Also, when the outboard motor main body and the swivel bracket are turned up about the tilt shaft by the tilt mechanism, the steering mechanism turns about the tilt shaft and approaches the stern plate.